Crystalline molecular sieves are usually prepared from aqueous reaction mixtures containing sources of alkali or alkaline earth metal oxides sources of silicon oxide, and, optionally, sources of, e.g., boron oxide and/or aluminum oxide.
Molecular sieves have been prepared from reaction mixtures containing an organic structure directing agent (“SDA”), usually a nitrogen-containing organic cation. For example, U.S. Pat. No. 4,963,337, issued Oct. 16, 1990 to Zones, discloses that the molecular sieve designated SSZ-33 can be prepared using a tricyclo[5.2.1.02,6]decane quaternary ammonium cation SDA. U.S. Pat. No. 4,544,538, issued Oct. 1, 1985 to Zones, discloses a molecular sieve designated SSZ-13 which is made using an SDA derived from 1-adamantamine, 3-quinuclidinol, or 2-exo-aminonorbornane. U.S. Pat. No. 5,316,753, issued May 31, 1994 to Nakagawa, discloses a molecular sieve designated SSZ-35 made using an SDA comprising aza-polycyclic ring compounds. U.S. Pat. No. 5,653,956, issued Aug. 5, 1997 to Zones, discloses a molecular sieve designated SSZ-42 made using an SDA comprising a N-benzyl-1,4-diazabicyclo[2.2.2]octane cation or a N-benzyl-1-azabicyclo[2.2.2]octane cation.
A number of zeolite molecular sieves have been synthesized on a small scale that can be used to make potentially, unique catalysts having potentially attractive catalyst properties. An obstacle, to the further development of these materials is the high cost of making large scale quantities of the molecular sieve. The costs are particularly high and prohibitive when relatively large amounts of exotic structure directing agents (also known as templates) are needed to make satisfactory purity molecular sieves. Thus, it is highly desirable and, in fact, critical to develop methods to make commercial volumes of the molecular sieves at significantly reduced per pound cost. This can be done by greatly reducing the cost/amount of the structure directing agent used in the synthesis. The present invention provides a process to allow the synthesis of molecular sieves at greatly reduced cost by replacing some of the structure directing agent with less expensive compounds.
U.S. Pat. No. 5,785,947, issued Jul. 28, 1998 to Zones et al., discloses a method of preparing crystalline zeolites using a small quantity of an organic templating compound and a larger quantity of an amine component containing at least one amine having from one to eight carbon atoms, ammonium hydroxide, or mixtures thereof. It is disclosed that the amine component is preferably an aliphatic or cycloaliphatic amine containing no more than eight carbon atoms. Disclosed examples of the amine component are isopropylamine, isobutylamine, n-butylamine, piperidine, 4-methylpiperidine, cyclohexylamine, 1,1,3,3-tetramethyl-butylamine and cyclopentylamine.
U.S. Pat. No. 5,707,600, issued Jan. 13, 1998 to Nakagawa et al., discloses a process for preparing medium pore size zeolites using small, neutral amines capable of forming the zeolite, the amine containing (a) only carbon, nitrogen and hydrogen atoms, (b) one primary, secondary or tertiary, but not quaternary, amino group, and (c) a tertiary nitrogen atom, at least one tertiary carbon atom, or a nitrogen atom bonded directly to at least one secondary carbon atom, wherein the process is conducted in the absence of a quaternary ammonium compound. Disclosed examples of the small, neutral amine are is isobutylamine, diisobutylamine, trimethylamine, cyclopentylamine, diisopropylamine, sec-butylamine, 2,5-dimethylpyrrolidine and 2,6-dimethylpiperidine.
U.S. Pat. No. 5,707,601, issued Jan. 13, 1998 to Nakagawa, discloses a process for preparing zeolites having the MTT crystal structure using small, neutral amines capable of forming the zeolite, the amine containing (a) only carbon, nitrogen and hydrogen atoms, (b) one primary, secondary or ternary, but hot quaternary, amino group, and (c) a tertiary nitrogen atom, at least one tertiary carbon atom, or a nitrogen atom bonded directly to at least one secondary carbon atom, wherein the process is conducted in the absence of a quaternary ammonium compound. Disclosed examples of the small, neutral amine are isobutylamine, diisobutylamine, diisopropylamine and trimethylamine.
U.S. Pat. No. 7,022,308, issued Apr. 4, 2006 to Yuen et al., discloses a method for preparing molecular sieve SSZ-33 having a mole ratio of greater than about 15:1 of (1) silicon oxide, germanium oxide and mixtures thereof to (2) boron oxide or a mixture of boron oxide with aluminum oxide, gallium oxide, titanium oxide or iron oxide and mixtures thereof, said method comprising:    A. forming an aqueous reaction mixture comprising (1) a source of silicon oxide, germanium oxide and mixtures thereof; (2) a source of boron oxide or a mixture of boron oxide with aluminum oxide, gallium oxide, titanium oxide or iron oxide and mixtures thereof; (3) a source of alkali metal or alkaline earth metal; (4) an N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.02,6]decane quaternary ammonium cation, and (5) an N,N-dialkyl-8-amino-tricyclo[5.2.1.02,6]decane compound; and    B. maintaining said aqueous mixture under sufficient crystallization conditions until crystals are formed.